How to configure embeded typescript-language-server?

I'm plagued by the diagnostic message File is a CommonJS module; it may be converted to an ES module. [80001].

I know it's coming from tsserver itself and passes through the internal handler typescript-language-server somehow.
I can configure tsserver itself by placing a file at the right location, but that only allows to fully disable all diagnostics, which is not helpful at all.
I know the typescript-language-server allows to configure ignores on a more granular level, as documented here.

But i can't for the life of me find out just HOW i get to pass the needed config values through eclipse. And the web developers settings pages for language server configurations are pretty lacking in that department, if existing at all.

Do i really have to define an external language server launch configuration, just to somehow get some options changed? Or is there some kind of well-known file for the typescript-language-server that is magically detected and read when in the workspace/project root?

Start with docs/configuration.md, especially its configuration section, then review the Eclipse Web Developer settings pages and the issue's described tsserver and typescript-language-server flow. Determine whether the needed configuration is supported through Eclipse or requires an external launch configuration, and document the supported setup and configuration location.